Commit 497728e1 authored Jan 01, 2012 by Jeff Layton Committed by Steve French Jan 03, 2012

cifs: fix bad buffer length check in coalesce_t2



The current check looks to see if the RFC1002 length is larger than
CIFSMaxBufSize, and fails if it is. The buffer is actually larger than
that by MAX_CIFS_HDR_SIZE.

This bug has been around for a long time, but the fact that we used to
cap the clients MaxBufferSize at the same level as the server tended
to paper over it. Commit c974befa changed that however and caused this
bug to bite in more cases.

Reported-and-Tested-by: Konstantinos Skarlatos <k.skarlatos@gmail.com>
Tested-by: Shirish Pargaonkar <shirishpargaonkar@gmail.com>
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <smfrench@gmail.com>

parent f9fab10b

fs/cifs/connect.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -282,7 +282,7 @@ static int coalesce_t2(struct smb_hdr psecond, struct smb_hdr pTargetSMB)
		byte_count = be32_to_cpu(pTargetSMB->smb_buf_length);
		byte_count += total_in_buf2;
		/* don't allow buffer to overflow */
		if (byte_count > CIFSMaxBufSize)
		if (byte_count > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE - 4)
		return -ENOBUFS;
		pTargetSMB->smb_buf_length = cpu_to_be32(byte_count);

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